Temporal lobe epilepsy (TLE) is the most common epilepsy in adults. TLE is often refractory to current anti- epileptic drugs, and systemic treatments are frequently accompanied by significant negative side effects. However, the cellular and circuit mechanisms underlying TLE are not yet understood, which poses a challenge for the development of novel treatment strategies. Recently, we discovered that closed-loop optogenetic intervention (COI) can significantly curtail on-going electrographic and behavioral seizures in chronic experimental TLE with high spatial, temporal, and cell-type specificity, and that it can be used as a powerful, versatile research tool for hypothesis testing o understand TLE mechanisms. Here we propose to test the hypothesis that COI achieves long-term seizure control, as well as the amelioration of cognitive comorbidities and pathological functional network properties, during both the chronic and latent phases of TLE. The hypothesis will be tested in experimental mouse models of TLE, and the assessment will be carried out with electrophysiological and behavioral techniques as well as large-scale in vivo functional imaging methods in the CA1 region of the mouse hippocampus. It is anticipated that defining the functional consequences of COI in TLE will have a significant impact by advancing our understanding of the role of activity-dependent pathological processes in chronic epilepsy and epileptogenesis, and aid the future development of novel anti-epileptic treatment strategies.